The present invention improve the graininess of silver halide photographic light-sensitive materials is an important subject in the field of such photographic materials and much information relating thereto has been accumulated.
For instance, Japanese Patent Application (OPI) No. 62454/80 discloses the use of a high speed reactive coupler, wherein graininess in high density image areas is markedly improved. This is because such a coupler reacts rapidly with the oxidation product of a color developing agent and, consequently, a development restraining effect caused by the oxidation product of color developing agent is diminished and, at the same time, the amount of developed silver in highly exposed areas is increased. Under these conditions, all of the coupler molecules coated undergo the reaction and thereby any granular condition becomes inconspicuous, that is to say, disappearance of the granular structure occurs quickly. However, high speed reactive couplers have a serious defect that they form dye clouds of high densities due to the rapid reaction with the oxidation products of color developing agents and thereby graininess in low density image areas is extremely deteriorated.
In order to eliminate such a defect, methods of using high speed reactive couplers in combination with the so-called DIR couplers of DIR compounds, which tend to break up dye clouds into fine pieces improving graininess are disclosed in U.S. Pat. Nos. 3,227,554 and 3,632,435, respectively. However, such methos are not desirable because restrainers released upon development counteract the effect of the high speed reactive couplers, that is, the effect of improving the graininess in high density image areas is suffered.
On the other hand, U.S. Pat. No. 3,457,079 discloses gallic acid esters added to silver halide emulsion layers. Color formers are disclosed. However, the gallic acid esters are not employed in combination with any high speed reactive type couplers. The gallic acid esters of the U.S. patent are used to stabilize silver halid emulsion during storage prior to exposure. As a natural consequence, no graininess problem is taken into accout.